A vehicle seat is set in a vehicle slidably in front and rear directions by a sliding mechanism. With respect to a seat sliding mechanism set at driver's seat, a position sensor which detects the position of a seat body (such as a seat and a sheet back) along front and rear directions can be provided in order to control the operation of an air bag module provided in a steering wheel.
The position sensor is supported by a bracket which extends laterally from a lower rail provided on the side of a vehicle floor. An upper rail is provided on the side of the seat body. The position sensor detects the position of the seat body depending on whether a detected portion fixatedly provided on the side surface of the upper rail is positioned opposite to the detection portion of the position sensor (refer to Patent Document 1).